1. Field of the Invention
The present invention relates generally to connectors for differential transmission, and more particularly to a connector for differential transmission employed for connection to computer apparatuses.
2. Description of the Related Art
Differential transmission has been employed in many cases as a method of transmitting data between personal computers and peripheral devices. Differential transmission uses a pair of lines for each data element, and simultaneously transmits a “+” signal to be transmitted and a “−” signal equal in magnitude and opposite in direction to the “+” signal. Differential transmission has the advantage of being less susceptible to noise compared with a normal transmission method.
When the distance between a server apparatus and a computer apparatus is short, the server apparatus and the computer apparatus may be connected satisfactorily with an electric wire cable. However, if the server apparatus and the computer apparatus are remote from each other, it is desirable to substitute an optical fiber cable for the electric wire cable in view of the reliability of signal transmission.
FIG. 1 is a diagram showing a conventional cable-type plug connector for differential transmission 10 employed to connect computer apparatuses. The differential transmission plug connector 10 includes a connector main body 11, a housing 12, and a plug part for differential transmission 13. The connector main body 11 is incorporated in the housing 12 on its front end side. The plug part 13 projects from the housing 12 at the front end thereof. An electric wire cable 14 extends from the rear end of the housing 12.
Japanese Laid-Open Patent Application No. 2003-059593 discloses a conventional cable-type connector for differential transmission.
Conventionally, the plug connector of FIG. 1 is the only type of cable-type plug connector for differential transmission employed to connect computer apparatuses. Accordingly, a conventional server apparatus 20 has a jack connector for differential transmission 21 and an optical fiber connector 22 provided on its rear side, and has a built-in photoelectric conversion module 23 electrically connected to the optical fiber connector 22 as shown in FIG. 2.
When the server apparatus 20 is located a short distance from a computer, the server apparatus 20 is connected to the computer with the electric wire cable 14, using the plug connector 10. When the server apparatus 20 is located remote from the computer so that there is a long distance between the server apparatus 20 and the computer, an optical fiber connector 30 is connected to the optical fiber connector 22 so that the server apparatus 20 and the computer are connected with an optical fiber cable 31 so as to prevent the degradation of signal quality.
Thus, the server apparatus 20, which has two types of connectors, that is, the differential transmission jack connector 21 and the optical fiber connector 22, provided on its rear side and has the photoelectric conversion module 23 provided inside, is costly. In particular, the optical fiber connector 22 and the photoelectric conversion module 23 are unnecessary to users who use the server apparatus 20 at a location close to the computer, thus making the server apparatus 20 costly for the users.